Performance of Diversity System Output Signal in Mobile Cellular System in the Presence of alpha-mu all Short Term Fading and Gamma Long Term Fading

In this paper, wireless mobile communication system with macrodiversity reception is considered. Macrodiversity system is consisting of macrodiversity selection combining (SC) receiver and three microdiversity SC receivers. Propagation channel suffers alpha-mu short term fading and Gamma long term fading resulting in system performance degradation. Analytical closed form expression for average level crossing rate (LCR) of macrodiversity SC receiver output signal envelope is obtained Mathematical results are analyzed, presenting the influence of long term fading parameters and short term fading parameters on average level crossing rate. Obtained results can be used in the process of simulation and design of real-world environments mobile cellular telecommunication systems

Outage Probability of Macrodiversity Reception in the Presence of Fading and Weibull Co-Channel Interference

In this paper macrodiversity reception with macrodiversity selection combining (SC) receiver and two microdiversity SC receivers operating over Gamma shadowed Weibull multipath fading channel in the presence of co-channel interference subjected to Weibull short term fading is analysed. Closed form expression for cumulative distribution function (CDF) of signals at outputs of microdiversity receivers is calculated. These results are used for CDF evaluation of macrodiversity SC receiver output signal envelope. Series of derived expressions for outage probability rapidly convergence from 5 to 10 terms should be summed to achieve accuracy at 5th significant digit for any Gamma long term fading parameters and Weibull short term fading parameters. In this paper, influence of Gamma long term fading severity parameter, Gamma long term fading correlation coefficient and Weibull short term fading nonlinearity parameter on outage probability are analysed and discussed

Volcano plots along intermetallic hypo-hyper-d-electronic phase diagrams and electrocatalysis for hydrogen electrode reactions

The nature, causes and consequences of the existence of volcano plots along transition series with resulting theoretical conclusions have been extended on the Brewer hypo-hyper-d-electronic combinations of transition metal intermetallic phases. There has been pointed out that every such phase diagram behaves as the part of Periodic Table between two initial constituents, and thereby features the Gschneidner type volcano plots for the hydrogen electrode reactions (heir), in common with well known electrocatalytic volcano curves of H. Kita and M.H. Miles for the hydrogen evolution reaction (her) upon individual transition metals. Several typical Brewer intermetallic systems (Ti-Ni, Zr-Ni, Mo-Ni) were investigated and their comparable hydridic and electrocatalytic properties became revealed from volcanic plots along corresponding phase diagrams. In the light of such conclusions, there has been pointed out that catalytic volcano plots represent in their essence the main criterion and guidance leading to both optimal and synergetic electrocatalytic effects and (electro)catalysts for the heir of broader application in both industrial. electrolytic and catalytic processes and mobile fuel cells for hydrogen powered cars. As the consequence of the present theory, the paper has been used for the promotion of so called Tiney-Ni, as the counterpart of more common Raney-Ni catalyst and its advanced electrocatalytic and hydridic properties were illustrated and pointed out in the light of hypo-hyper-d-electronic features of composite Braver type intermetallic phases

Hydridic and electrocatalytic properties of hypo-hyper-d-electronic combinations of transition metal intermetallic phases

Hydridic and electrocatalytic properties of hypo-hyper-d-electronic combinations of transition metals in their intermetallic phases and alloys for the hydrogen storage, hydridic batteries and its electrode reactions (HELR) have been considered in the light of Fermi dynamics (or the electronic density of states), work function and the Brewer or Miedema intermetallic bonding theory (structural factors). It has been pointed out that such an intermetallic hypo-hyper-d-electronic interaction of transition metals (or the doped effect of a hyper-d- upon the bulk or surface of a hypo-d-electronic metal, or vice versa), which leads to the defined optimal mutual (bulk or surface) electronic density of states for both hydridic storage and/or electrocatalytic reaction (cathodic evolution (HER) and/or anodic oxidation (HOR) of hydrogen), imposes the same catalytic effect as the Non-Faradaic promotion by induced polarization, or the so-called NEMCA effect (Non-Faradaic Electrochemical Modification of Catalytic Activity). The main impact has been imposed on the most promising hydridic battery system (Ti-Ni, crystalline and sintered), as well as on typical electrocatalytic issues (Mo-Co, Mo-Ni, Zr-Ni). It has also been inferred that each phase diagram of a hypo-hyper-d-electronic combination of transition metals behaves in both the hydridic and electrocatalytic sense as the part of Periodic Table: intermetallic phases and alloys between two pure constituents obey typical volcano plots for both hydridic and catalytic activity in accordance with the changes in their electronic density of states and well-defined crystal structure, thereby resulting in intermetallic bonding effectiveness and a mutual work function

Kinetic properties of the Ti-Ni intermetallic phases and alloys for hydrogen evolution

The kinetics and mechanism of hydrogen evolution at Ti-Ni alloy electrodes prepared by are-melting and mechanical alloying methods has been studied by means of AC impedance spectrum measurements. The electrode, prepared by mechanical alloying (porous electrode), after activation in a 10% HF solution, is very active despite its large Tafel slope. The SEM studies show a formation of deep pores on the electrode surface. The rate constants of the forward and backward reactions of the corresponding steps were estimated by a nonlinear fitting method. It has been found that the overall reaction proceeds through a Volmer-Heyrovsky mechanism

The determination of kinetics parameters of the hydrogen evolution on Ti-Ni alloys by ac impedance

The kinetics and mechanism of hydrogen evolution at Ti-Ni alloys electrode has been studied by means of steady-state potentiostatic polarization and ac impedance spectrum measurements. Complex-plane spectrum plots are derived for the h.e.r. at one of the most inactive, typical hydridic, Ti-Ni, and one of the most active, typical electrocatalytic, Ti-Ni-3, intermetallic alloy compounds at various potentials. The rate constants of the forward and backward reactions of the corresponding steps were estimated by a nonlinear fitting method. It has been found that the overall reaction proceeds through a coupled Volmer-Heyrovsky mechanism. The electrocatalytic activity decreases in the order TiNi2 gt TiNi3 gt TiNi4 gt Ti2Ni gt TiNi gt Ti3Ni gt TiNi0.7